Pixar Reinvents Big Hair for Brave

Merida's hair, and the rest of a scene, are rendered completely.
Character Art: Director Matt Nolte

Before the final shots are rendered, this wireframe calculates the "core curves" of Merida's hair, based on the original concept art.
Illustration: Disney/Pixar

The original concept art.
Illustration: Tia Kratter

In the ’80s, when you wanted big hair you whipped out the Aqua Net. But it wasn’t so easy for animators. The Little Mermaid‘s Princess Ariel was meant to sport curls, but the technology just wasn’t there in 1989—rendering that kind of bounce and frizz, cel after hand-drawn cel, was all but impossible. Now, though, animated big hair is finally on the big screen in Disney/Pixar’s Brave.

The movie centers on Merida, a feisty Scottish princess on a quest to save her kingdom from a curse. To illustrate her fiery spirit, filmmakers wanted Merida’s locks to spring off the screen—”Curly hair almost defies gravity,” simulation supervisor Claudia Chung says—but Pixar’s old CG hair simulator (used in 2001’s Monsters, Inc.) wasn’t up to the task.

So in 2009 Chung’s team designed a new simulator named Taz, after the wild Looney Tunes character. It forms individual coils around computer-generated cylinders of varying lengths and diameters. The resulting locks stretch out when Merida runs but snap back into place as soon as she stops. Each strand is also strung through with a flexible “core curve,” like the string of a beaded necklace, that lets the coils bounce and brush against one another without unwinding.

Add a little randomness, some gravity, and more than 1,500 hand-placed corkscrews and flyaway wisps and voilà: hair with depth and texture viewers have never seen before. The result may look wild, but it’s not. “It’s very stylized, very controlled,” Chung says. No hair spray required.